1. Field of the Invention
This invention relates to novel benzoyl indolecarboxylates.
More specifically, the invention relates to benzoyl indolecarboxylates represented by the following formula (I) and their acid addition salts: ##STR2## wherein
R.sub.1 is a hydrogen or halogen atom, or a lower alkoxy or lower alkoxy group;
R.sub.2 is a hydrogen atom, or a lower alkyl, acetyl or benzoyl group;
R.sub.3 is a hydrogen atom or a lower alkyl group; and
A is a direct bond, or a lower alkylene or vinylene group substituted at the 2-, 3- or 5-position of the indole nucleus.
2. Description of the Prior Art
The present inventors have previously found various benzoyl indolecarboxylates which can exert excellent chymotrypsin inhibitory characteristics, as disclosed in Japanese Patent Publication (Kokai) No. 38243/58 (1983).
Through continuous research efforts directed to the syntheses of a homologous series of compounds and to the determinations of their physiological activities, it has now been discovered that compounds of the formula (I) above and their acid addition salts have more specific inhibitory effects on chymotrypsin.